Array antenna system, delay amount setting device, wireless transmitter, and program

Abstract

The wireless transmitters that make up an array antenna system have their own inherent delay times, and when the spectrum of the spatially combined transmitted radio waves is distorted due to this effect, intersymbol interference occurs. [Solution] The array antenna system according to the disclosed technology comprises a transmission sequence generator and N wireless transmitting devices. Each wireless transmitting device comprises a modulator that generates a baseband signal, an amplitude-phase adjuster that adjusts the amplitude and phase of the baseband signal, a delay compensator that adjusts the time of the baseband signal, an IF frequency converter that converts the baseband signal into an intermediate frequency signal, an IF circuit that adjusts the intermediate frequency signal, an RF frequency converter that converts the intermediate frequency signal into a radio frequency signal, an RF circuit that adjusts the RF frequency signal, and a transmitting antenna. The delay compensator adjusts the time so that the delay amounts of all N wireless transmitting devices are equal.

Description

[Technical Field]

[0001] The disclosed technology relates to a wireless communication transmitter that transmits broadband information signals. More specifically, it relates to reducing intersymbol interference caused by delay characteristic differences between branches in an array antenna transmitter that performs directional control. [Background technology]

[0002] Discussions have begun regarding the sixth-generation mobile communication system (hereinafter referred to as "6G"). One of the requirements for 6G is ultra-high speed exceeding 100 Gbps. One method to satisfy this condition is to further widen the signal bandwidth. If the signal bandwidth is multiplied by L, the channel capacity, which can be derived from the Shannon-Hartley theorem, will also be multiplied by L. The signal bandwidth for the fifth-generation mobile communication system (5G) was a maximum of 100MHz for carrier frequencies below 6GHz and a maximum of 400MHz for carrier frequencies above 6GHz.

[0003] To ensure a wide bandwidth, 6G utilizes a higher frequency band than 5G. Generally, the higher the frequency, the narrower the range of radio waves. Array antenna technology is a technique for extending the range of radio waves emitted from an antenna (Non-Patent Literature 1). Array antenna technology controls the directivity of radiated radio waves by transmitting the same signal from multiple antennas and controlling the phase difference between these signals. This allows for high gain in the desired direction while reducing the amount of radio wave radiation in unintended directions. Furthermore, on the receiving end, the direction of arrival of radio waves can be estimated by receiving multiple identical signals with equal phase differences from multiple antennas. Alternatively, by controlling the phase difference, the directivity of the received radio waves can be controlled, allowing only radio waves from the desired direction to be received. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] IEICE (Institute of Electronics, Information and Communication Engineers), "Forest of Knowledge, Group 4, Part 2, Chapter 7: Array Antennas," [Retrieved March 28, 2025], Internet <https: / / www.ieice-hbkb.org / files / 04 / 04gun_02hen_07.pdf> [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] A wireless transmission device consists of devices that perform processing on the transmitted signal, such as filtering, frequency conversion, and amplification. Each device then experiences its own inherent delay. Because there are individual differences in the amount of delay between devices, the transmitted signal is transmitted with a delay equal to the sum of the delays in each device across the entire transmission device. This sum of delays across each transmission device will be called the "inherent delay time."

[0006] Array antenna systems, which control the directivity of transmitted radio waves, generally consist of multiple radio transmitters. Each transmitter emits the same signal as radio waves, and the directivity of the spatially combined transmitted radio waves is controlled by controlling the phase difference of the emitted radio waves. On the other hand, when the transmitted signal is widened, the time per bit decreases, and if the spectrum of the spatially combined transmitted radio waves is distorted due to the delay difference in each transmitter, inter-symbol interference (ISI) occurs. Furthermore, if the bandwidth is increased and the ISI becomes even larger, it can cause code errors. Therefore, a challenge in array antenna systems is to reduce the difference in the amount of delay of each radio transmitter. [Means for solving the problem]

[0007] The array antenna system according to the disclosed technology, which solves the above problems, comprises a transmission sequence generator that generates a transmission signal sequence, N wireless transmitting devices, and N transmitting antennas that radiate the transmission signal. The nth wireless transmitter (n=1,2,…,N) comprises: an nth modulator that modulates the transmission signal sequence and generates a baseband frequency signal; an nth amplitude-phase adjuster that adjusts the amplitude and phase of the baseband frequency signal; an nth delay compensator that adjusts the time of the signal output by the nth amplitude-phase adjuster; an nth IF frequency converter that converts the signal output by the nth delay compensator into an intermediate frequency signal; an nth IF circuit that causes a delay in conjunction with the adjustment of the signal output by the nth IF frequency converter; an nth RF frequency converter that converts the signal output by the nth IF circuit into a radio frequency signal; and an nth RF circuit that causes a delay in conjunction with the adjustment of the signal output by the nth RF frequency converter. The nth delay compensator adjusts the time so that the delay amounts of all N wireless transmitters are equal. [Effects of the Invention]

[0008] According to the disclosed technology, the inherent delay time of each wireless transmitter can be compensated, and an array antenna system can be constructed with wireless devices that have uniform delay amounts, thus preventing spectral distortion and suppressing ISI. [Brief explanation of the drawing]

[0009] [Figure 1] Functional block diagram of the array antenna system according to the first embodiment. [Figure 2] Functional block diagram of the array antenna system according to the second embodiment. [Figure 3] Detailed functional block diagram of the delay amount setting device. [Figure 4] A flowchart explaining the operation of the delay amount setting device. [Figure 5] A diagram illustrating the relationship between the transmitted signal sequence, the delayed signal sequence, the regenerated signal sequence, and the nth RF delay. [Figure 6] Spectral diagram of a signal transmitted at a baud rate of 1 GHz from an array antenna system with N=2, and received. [Figure 7] Spectral diagram of a transmission signal with a baud rate of 3 GHz transmitted from and received by an array antenna system with N=2. [Figure 8]A diagram showing an example of the functional configuration of a computer. [Description of Embodiments]

[0010] The disclosed technique is summarized as performing compensation to equalize the delay amount between each wireless transmission device for an array antenna system configured with a plurality of wireless transmission devices. Hereinafter, embodiments of the disclosed technique will be described in detail. Components having the same function are denoted by the same reference numerals, and redundant descriptions are omitted.

[0011] [First Embodiment] Figure 1 is a functional block diagram showing a configuration example of the array antenna system according to the first embodiment. The array antenna system 1 includes a transmission sequence generator 101 and N systems of wireless transmission devices 10-1 to 10-N. The n-th wireless transmission device 10-n (n=1,2,…,N) includes an n-th modulator 102-n, an n-th amplitude and phase adjuster 103-n, an n-th delay compensator 104-n, an n-th IF frequency converter 105-n, an n-th IF circuit 106-n, an n-th RF frequency converter 107-n, an n-th RF circuit 108-n, and an n-th transmit antenna 120-n.

[0012] <Functions of Components of Wireless Device> The n-th modulator 102-n modulates the transmission signal sequence generated by the transmission sequence generator to generate a baseband frequency signal. In the n-th modulator 102-n, modulation is performed on the same transmission signal sequence by the same method. Accordingly, the output signal of the n-th modulator 102-n is the same signal for n=1,…,N, so for example, modulation may be performed using only the first modulator, and the output thereof may be distributed into N parts. In any case, the same signal in the baseband frequency band is input to the n-th amplitude and phase adjuster 103-n.

[0013] The nth amplitude-phase adjuster 103-n adjusts the amplitude and phase of the output signal from the nth modulator to control the directivity of the transmitted radio waves. The amplitude and phase adjusted by the nth amplitude-phase adjuster 103-n are given by a fundamental relation that determines the radiation directivity in the array antenna.

[0014] The nth delay compensator 104-n applies a delay calculated by the method described later to the baseband signal after amplitude and phase adjustment.

[0015] The output signal of the nth delay compensator 104-n is frequency-converted to the intermediate frequency band by the nth IF frequency converter 105-n.

[0016] The signal in the intermediate frequency band passes through the nIF circuit 106-n, which consists of a filter to suppress unwanted waves generated during frequency conversion and an amplifier to amplify them. Filtering and amplification processes require a predetermined amount of time (they are processes that involve delays).

[0017] The nth RF frequency converter 107-n converts the frequency of the output signal from the nth IF circuit to a radio frequency.

[0018] The output signal of the nth RF frequency converter 107-n passes through the nth RF circuit 108-n, which consists of a filter that suppresses unwanted waves generated during frequency conversion and an amplifier that determines the transmission power from the antenna. This process also involves a delay.

[0019] The output of the nth RF circuit 108-n (nth RF signal) is radiated from the nth transmitting antenna 120-n. The radiated radio waves are strongly radiated in a direction determined by the amplitude and phase adjusted by the nth amplitude and phase adjuster 103-n.

[0020] <Effects of delay compensation> The effect of delay compensation by the nth compensated delay device 104-n will be explained. Figure 6 shows the spectrum obtained when a baud rate 1 GHz transmission signal was transmitted from the antenna to the array antenna system with N=2 as shown in Figure 1, and received. There is no distortion within the bandwidth, confirming that the radio waves are being radiated in the direction of the receiver. Furthermore, the signal transmission quality was also good, with an EVM (Error Vector Magnitude: modulation accuracy) of 20 dB or more being secured.

[0021] Figure 7(a) shows the spectrum when a baud rate 3 GHz transmission signal is transmitted from the antenna and received using the array antenna system with N=2 as shown in Figure 1. A large dip is observed within the bandwidth. Furthermore, the signal transmission quality deteriorated, resulting in a situation where reception was impossible. This dip in the spectrum is due to the delay time difference between each wireless transmitter constituting the array antenna system.

[0022] Figure 7(b) shows the spectrum when a baud rate 3 GHz transmission signal is transmitted from an array antenna system with N=2, compensating for the delay time difference between these wireless transmitters, and received. The in-band dip observed in Figure 7(a) has been eliminated, and the signal transmission quality has also improved, with an EVM of 20 dB or more being secured. The method for compensating for delays involves measuring the delay for each wireless transmitter and adjusting the delay time of other wireless transmitters using a delay compensator so that they have the same delay as the wireless transmitter with the largest delay. A delay compensator can be implemented, for example, by a variable delay line.

[0023] The above is a description of the first embodiment.

[0024] [Second Embodiment] In the first embodiment, a configuration in which a compensating delay device is placed in each wireless transmitter and its effects were described. In the second embodiment, a method and apparatus for automatically and dynamically setting the compensation amount for the compensating delay device will be described.

[0025] Figure 2 is a functional block diagram showing an example configuration of an array antenna system according to the second embodiment. Array antenna system 2 differs from array antenna system 1 in that each transmitting device is equipped with an nth RF signal distributor 109-n and a delay amount setter 110. The nth RF signal distributor 109-n transmits the nth RF signal to the delay amount setter 110. Figure 3 is a detailed functional block diagram of the delay amount setter 110. The delay amount setter 110 comprises an nth delay unit 301-n, an nth demodulation unit 302-n, and an nth BB frequency converter 303-n. Figure 4 is a flowchart illustrating an example of the operation of the delay amount setter 110. Figure 5 illustrates the relationship between the transmitted signal sequence, the delayed signal sequence, the regenerated signal sequence, and the nth RF delay amount, which will be described later. This will be explained using Figures 2, 3, 4, and 5.

[0026] The delay amount setter 110 estimates the intrinsic delay time of each wireless transmitter by comparing the transmission signal sequence regenerated from the RF signal acquired from the RF circuit with the transmission signal sequence acquired from the transmission sequence generation unit 101, while adding a predetermined delay in increments. In the following explanation, the predetermined increment will be described as δ seconds, and the maximum delay to be added will be K × δ seconds.

[0027] The delay amount setter 110 initializes the counter k to 1 (step S401). The nth BB frequency converter 303-n receives the nth RF signal from the nth RF signal distributor 109-n and converts it into an nth baseband frequency signal (step S402). The nth demodulation unit 302-n demodulates the nth baseband frequency signal to produce the nth regenerated signal sequence D n Generate (n=1,2,…,N) (Step S403, 501 in Figure 5).

[0028] The delay amount setter 110 simultaneously acquires the transmission signal sequence S (502 in Figure 5) from the transmission sequence generation unit 101 (step S404) and distributes it to the nth delay unit (n=1,2,...,N). The n-th delay unit generates a delayed signal sequence Sk by delaying the transmission signal sequence S by kδ seconds (step S405, 503 in Figure 5). The delay amount setter 110 calculates the correlation between D n and S k (step S406). This is denoted as C k n (504 in Figure 5). The delay amount setter 110 increments the counter k by 1 (step S407), and repeats steps S402 to S407 until k exceeds K. That is, for each n (for each wireless transmission device), C1 n to C K n are calculated.

[0029] The correlation detection yields a high detection result value when S k and D n are completely identical. Therefore, by specifying the delay amount given by the n-th delay unit when the detection value is maximum, the delay time of each wireless transmission device can be detected. The delay amount setter 110 determines k that gives the maximum value among C1 n to C K n , and sets the n-th RF delay amount = Δ n = k×δ (505 in Figure 5). Further, the maximum value among Δ 1 to Δ N is defined as Δ MAX (step S409). The delay amount setter 110 calculates Δ MAX - Δ n , and sets the result as the delay amount d to be set in the n-th delay compensator 104-n of the n-th wireless transmission device 10-n n (step S410, 506 in Figure 5).

[0030] The above is the description of the second embodiment. Note that the update of the delay amount of each wireless transmission device by the delay amount setter may be performed periodically, or may be implemented when the signal transmitted by the array antenna is received (monitored) and the transmission quality falls below a predetermined reference.

[0031] [Program, Recording Medium] The functions realized by the components described herein may be implemented in a circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (a Central Processing Unit), conventional circuits, and / or combinations thereof, programmed to realize the functions described herein. A processor includes transistors and other circuits and is considered a circuitry or processing circuitry. A processor may be a programmed processor that executes a program stored in memory.

[0032] In this specification, circuitry, unit, and means are hardware programmed to perform or execute the functions described herein. Such hardware may be any hardware disclosed herein, or any hardware known to be programmed to perform or execute the functions described herein.

[0033] If the hardware is a processor that is considered to be a type of circuitry, then the circuitry, means, or unit is a combination of hardware and software used to constitute the hardware and / or processor.

[0034] The various processes described above can be carried out by loading a program that executes each step of the above method into the recording unit 2020 of the computer 2000 shown in Figure 8, and then causing the control unit 2010, input unit 2030, output unit 2040, display unit 2050, etc. to operate.

[0035] The program describing this process can be recorded on a computer-readable recording medium. Any computer-readable recording medium can be used, such as a magnetic recording device, optical disc, magneto-optical recording medium, or semiconductor memory.

[0036] Furthermore, this program may be distributed, for example, by selling, transferring, or lending portable recording media such as DVDs or CD-ROMs on which the program is recorded. Alternatively, the program may be stored in the storage device of a server computer and distributed by transferring the program from the server computer to other computers via a network.

[0037] A computer executing such a program may, for example, first store the program recorded on a portable storage medium or a program transferred from a server computer in its own memory. Then, when processing is to be executed, the computer reads the program stored in its memory and executes the processing according to the read program. Alternatively, the computer may directly read the program from the portable storage medium and execute the processing according to that program, or it may sequentially execute the processing according to the received program each time a program is transferred to it from a server computer. Furthermore, the processing may be executed by a so-called ASP (Application Service Provider) type service, where the processing function is realized only by execution instructions and result acquisition, without transferring the program from the server computer to this computer. Moreover, the processing may be executed using a so-called SaaS (Software as a Service) type service, where a part of the server computer is made available to the user along with the program. The above-mentioned program includes information used for processing by an electronic computer that is equivalent to a program (data that is not a direct instruction to the computer but has the property of defining the computer's processing).

[0038] Furthermore, although the above explanation assumes that the device is configured by executing a predetermined program on a computer, at least a part of these processes may be implemented in hardware. [Industrial applicability]

[0039] This invention can be used in array antenna systems. [Explanation of Symbols]

[0040] 1,2 Array antenna system 10 Wireless Transmitter 101 Transmission sequence generator 102 Modulator 103 Amplitude Phase Adjuster 104 Delay Compensator 105 IF Frequency Converter 106 IF circuit 107 RF Frequency Converter 108 RF circuit 109 RF signal splitter 110 Delay Amount Setting Device 120 Transmitting Antenna 301 Delay section 302 Demodulation Unit 303 BB Frequency Conversion Unit 2000 Computer 2010 Control Unit 2020 Records Department 2030 Input Section 2040 Output Section 2050 Display section

Claims

1. A transmission sequence generator that generates a transmission signal sequence, N wireless transmitters, It comprises N transmitting antennas that radiate a transmission signal, The nth wireless transmitter (n = 1, 2, ..., N) is An nth modulator modulates the aforementioned transmission signal sequence and generates a baseband frequency signal, An nth amplitude-phase adjuster that adjusts the amplitude and phase of the baseband frequency signal, An nth delay compensator that adjusts the time of the signal output by the nth amplitude phase adjuster, The nth IF frequency converter converts the signal output by the nth delay compensator into an intermediate frequency signal, The nth IF circuit generates a delay in conjunction with the adjustment of the signal output by the nth IF frequency converter, The nth RF frequency converter converts the signal output by the nth IF circuit into a radio frequency signal, The system comprises an nth RF circuit that causes a delay in conjunction with the adjustment of the signal output by the nth RF frequency converter, The n-th delay compensator performs the time adjustment so that the delay amounts of all N wireless transmitters are equal. Array antenna system.

2. The array antenna system according to claim 1, The nth RF signal distributor distributes the signal output by the nth RF circuit, It also includes a delay amount setter, The aforementioned delay amount setter is The nth BB frequency conversion unit converts the signal output by the nRF signal distributor into a baseband frequency signal, A nth demodulation unit that demodulates the baseband frequency signal and reconstructs the transmitted signal sequence, The system includes an nth delay unit (n = 1, 2, ..., N) that delays the transmission signal sequence output by the transmission sequence generator, Based on the signal output by the nth demodulation unit and the signal output by the nth delay unit, the nth RF delay amount is identified, and the difference between the maximum delay amount among the first RF delay amount and the nth NRF delay amount and the nth RF delay amount is set in the nth delay compensator. Array antenna system.

3. The array antenna system according to claim 2, Let δ be a predetermined unit delay time and K be a predetermined integer, The nth delay unit is a delayed signal sequence S obtained by delaying the transmitted signal sequence by δ × k. k Generate (k = 1, 2, ..., K), The delay amount setter calculates the correlation C between the n-th reproduced signal sequence output by the n-th demodulation unit and the Sk k n , and C 1 n to C K n the C that is the maximum value among them k n the corresponding δ×k is set as the n-th RF delay amount Array antenna system.

4. A device for determining the delay amount of each wireless device in an array antenna system composed of N wireless devices, A demodulation unit that reconstructs the transmitted signal sequence based on the RF signal received from the nth wireless device (n = 1, 2, ..., N), The system includes an nth delay unit that imposes a delay on the transmission signal sequence received from the transmission sequence generation unit, Based on the signal output by the nth demodulation unit and the signal output by the nth delay unit, the nth RF delay amount is determined, and the difference between the maximum delay amount among the first RF delay amount and the nth RF delay amount and the nth RF delay amount is set as the delay amount of the nth radio device. Delay amount setting device.

5. A wireless transmitting device that constitutes an array antenna, A modulator that modulates the transmitted signal sequence to generate a baseband frequency signal, An amplitude-phase adjuster that adjusts the amplitude and phase of the baseband frequency signal, A delay compensator that adjusts the time of the signal output by the amplitude phase adjuster, An IF frequency converter that converts the signal output by the delay compensator into an intermediate frequency signal, An IF circuit that causes a delay in the adjustment of the signal output by the aforementioned IF frequency converter, An RF frequency converter that converts the signal output by the IF circuit into a radio frequency signal, An RF circuit that causes a delay in adjusting the signal output by the RF frequency converter, An RF signal distributor that distributes the signals of the RF circuit, It comprises a transmitting antenna that radiates a transmission signal, The RF signal distributor transmits the signal output by the RF circuit to a delay amount setter that determines the delay amount of all wireless devices constituting the array antenna. The delay compensator performs the time adjustment according to the instructions of the delay amount setter. Wireless transmitter.

6. A program for causing a computer to function as a delay amount setting device according to claim 4.

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